Automatic switch



May 21, 1940.

J. HOLIDAY AUTOMATIC SWITCH Filed Oct. 26, 1938 Qwuwwtoo vMm,

Patented May 21, 1940 ourrso SATES PATENT OFFICE AUTOMATIC SWITCH JulianHoliday, Springdale, Ky.

Application October 26, 1938, Serial No. 237,149

The present invention relates to a device applicable to a typical threewire lazy mans circuit, whereby current may be drawn from the circuitwithout interruption.

More precisely, the invention comprises a magnetic relay applicable to atypical three wire lazy mans circ Lit operable on either closed positionof the double throw switch thereof to maintain a constant anduninterrupted current in a secondary two wire circuit connected acrossthe three wire circuit.

is device is simple in construction and operation, and may be readilyapplied to the existing three wire circuit without alteration thereof,no additional wires from the rimary source of power being necessary.

The construction and details or the invention will now be described withreference to the ac companying figure, wherein a diagrammatic plan viewof the device is shown.

In the figure a typical lazy mans three wire circuit is shown connectedto the positive and negative wires 6 and 2 of the main line from theprimary source of power; The three wire lazy mans circuit comprisesbriefly two positive wires 3 and i, connected to the positive wire l ofthe main line by way of a two-way switch 5, and a negative wire iconnected directly to the negative wire 2 of the main line. The circuitis completed through a two-way switch 1, whereby the wires 3 i may beselectively connected to one side of the load or electrically operablemember 8 which comprise a group of lamps in series or parallel, theother side of the load being connected to the negative wire 5.

It may be desirable, in many instances, to cutin a secondary circuit onthe three wire circuit just described intermediate the ends of the sameto obtain current for operating some electrical household device, suchas a vacuum cleaner, coifee pot or electric fan. It is apparent from thewiring of the three wire circuit that when one of the positive wires isconnected by way of the switch 5 to the source of power, the other isnecessarily disconnected therefrom, depending upon which way the switch5 is thrown. In order, therefore, to maintain an uninterrupted currentin the secondary circuit, such as is designated by the wires 9 and ill,the terminals of which are connected to a wall socket or directly to theterminal of a load H, it is necessary to have some automatic means forselectively connecting the positive wire It to the energized wire of thepositive wires 3 and i. That is, it is desirable to have current flowinto the wall socket or through the (Cl. I'll-97) load H irrespective oithe position of the switch 5, and in order to maintain a' constantcurrent the wire Ill must at all times be connected to the energizedwire of the two positive wires 3 and 4.

The device hereinafter described is adapted to be readily applied to athree wire circuit, such as was described heretofore. It comprises apair of contacts 12 and i3 arranged to be slidably engaged by abridge-shaped slide M, the distance between the contacts being slightlygreater than the length of the slide M, so that in its movement theslide will at no time be in engagement with more than one of thecontacts. Contact I2 is wired to the positive wire 3 by way of the wiresl5 and 17, while contact i3 is wired to the positive wire 4 by way ofthe wires I6 and I8.

The bridge-shaped slide I4 is attached to the surface of a tubularmember 19 and extends longitudinally thereof, the slide beingelectrically in- 20 sulated from the tube by a non-conductive piece ofmaterial 29' extending beneaththe legs of the slide. A terminal 2| issecuredto the middle of the slide I4 to which is attacheda wire 22having a flexible portion 23 adjacent the terminal 2| so as to permitthe tube to move the bridge from one contact to the other. The wire 22is connected to the wire iii and constitutes the means whereby currentis supplied to the wire IE].

The tube It, at least the ends 24 and 25 of which are formed ofmagnetically attractive material, is arranged for movement between theends of a pair of axially aligned coils 28 and 21 provided withmagnetizable cores 28 and 29. The coils 2B and 21 are connected at oneend by the wires 30 and 3|, respectively, to the negative wire iiby wayof a wire 32 which may or may not be an extension of the wire 9. Theopposite ends of the coils are connected by wires H and 18 to thepositive wires 3 and 4, respectively.

The device operates as follows: Let it be supposed that a load has beenplaced across the wires 9 and Ill, and that the switches 5 and l occupythe full line positions shown so as tocomplete a circuit .from thepositive wire I through switch 5, wire 4, switch I, lamp 8 and wire 8'to the negative wire 2. Thewire 4 being energized, current will alsopass through the wire I 8, thereby energizing. the coil 21. The tube [Sin response to the magnetized core 29 of the coil 21 will move towardthe coil 21, and thereby cause engagement of the contact l3 and theslide l4, whereby a current is established from wire 4 through wires l8and I 6, contact l3 and wire 22 to the positivewire I0, thus completing'circuit connecting the second operable member the circuit necessary tooperate the device ll. Suppose now that the current has beenestablished, someone turns the lamp 8 off by throwing the switch 5 tothe dotted line position, thereby cutting the current off in wire 4, butat the same time establishing a current in the wire 3. If there were nosuch automatic means as described above, the device I! would immediatelycease to operate and it would be necessary to transfer the wire ID fromits connection with the dead wire 4 to the energized wire 3 in order tocontinue operation. This device, however, accomplishes the transferautomatically. As soon as the current is established in wire 3, the coil26 is energized thereby and the core 28 attracts the tube I9 toward thecoil so as to establish a current from the wire 3 through the wires I1,I 5, contact l2, and wire 22 to the positive wire II].

It is clear from the foregoing description of the operation of thedevice that the load H will be supplied with a constant source ofcurrent irrespective of the position of the switch 5.

The invention as described and illustrated in the drawing is notnecessarily limited to the par ticular arrangement herein shown, but maytake any form within the scope of the appended claims.

I claim:

1. In an electrical distribution system of the class described, thecombination with a main supply, a branch circuit connected to the mainsupply, said branch circuit including a three Wire circuit having one ofthe wires connected to one of the main supply leads, switch meansselectively connecting either of the other two wires to the other leadof the main supply, an electrically operable member connected to thefirst mentioned wire, switch means for controlling the connection of thebranch circuit to the operable member, a second operable member, asecondary to the branch supply, means for maintaining the electricconnection of the secondary circuit with the branch supply circuit whenthe current to the operable member is cut off, said means including amovable magnetically operable member connected to the branch circuitwhen the circuit to the operable member is closed, and means forautomatically moving said magnetically operable member to establish acircuit connection of the secondary circuit with the branch circuit whenthe circuit to the operable member is rendered inoperative.

2. In an electrical distribution system of the class described, thecombination with a main supply, a branch circuit connected to the mainsupply, said branch circuit including a three wire circuit having one ofthe wires connected to one of the main supply leads, switch meansselectively connecting either of the other two wires to the other leadof the main supply, an electrically operable member connected to thefirst mentioned wire, switch means for controlling the connection of thebranch circuit to the operable member, a second operable member, asecondary circuit connecting the second operable member to the branchcircuit, means for maintaining the electric connection of the secondarycircuit with the branch circuit when the current to the operable memberis cut off, said means including a pair of spaced fixed contactsindividually connected to the branch circuit, a movable contact arrangedalternately to engage one of the spaced contacts for establishing acircuit of the branch circuit with the secondary circuit, and means forbringing the movable contact into engagement with one of the fixedcontacts, whereby when the operable member is cut off from the branchcircuit, automatically to establish a circuit connection of the secondoperable member with the branch circuit.

3. In an electrical distribution system of the class described, thecombination with a main supply having a positive lead and a negativelead, a branch circuit including a three-wire circuit having one of thewires connected to the negative lead, a double switch for selectivelyconnecting the other two wires to the positive lead, an electricallyoperable member connected to the negative lead of the branch circuit,switch means for controlling the connection of the branch circuit to theoperable member, a second operable member, a secondary circuitconnecting the second operable member to the branch circuit, a pair ofspaced fixed contacts individually connected to one of the positiveleads of circuit, a movable contact arranged selectively to engage oneof the fixed contacts, magnetic means for actuating the movable contactto move the same in engagement with one of the fixed contacts when thebranch circuit is connected to the operable member, a second magneticmeans connected to the other fixed contact and to the branch circuit,said second magnetic means arranged to be energized to bring the movablecontact in engagement with the other of the fixed contacts when theoperable member is disconnected from the branch supply so asautomatically to establish an electrical connection between the secondoperable member and the branch circuit.

4. In an electrical distribution system of the class described, thecombination with the main supply having a positive lead and a negativelead, a branch supply including a three-wire circuit having one of theWires connected to the negative lead, a double switch selectivelyconnecting the other two wires to the positive lead, an electricallyoperable member connected to the negative lead of the branch circuit,switch means for controlling the connection of the branch circuit to theoperable member, a second operable member, a secondary circuitconnecting the second operable member to the branch supply between themain supply and the operable memher, a pair of spaced fixed contacts, amovable contact arranged selectively to engage one of the fixedcontacts, magnetic means associated with each of the fixed contacts,means for connecting the magnetic means to the branch circuit forenergizing the same, and means when the supply to the operable member iscut oil for automatically actuating one of the magnetic means to bringthe movable contact in engagement with its associated fixed contact soas automatically to establish a circuit through the secondary circuitwith the second operable member.

JULIAN HOLIDAY.

